This week, the Blotter is reprising seven different Brian Ross Unit investigations that made a difference in 2011. Today: McDonald's and Target drop the nation's fifth-largest egg producer after an ABC News probe.

A report that aired in November on "Good Morning America," "World News with Diane Sawyer" and "20/20" exposed alleged animal abuse and unsanitary conditions at Sparboe Farms, the nation's fifth-largest egg producer, which at the time supplied eggs to all McDonald's restaurants west of the Mississippi River.

Hidden camera footage shot at Sparboe Farms locations in three states by an undercover operative for the animal-rights group Mercy for Animals documented the apparent torture and killing of hens and chicks. The video also showed rodents and flies within the facilities, and dead birds in cages, all conditions experts say are conducive to the spread of salmonella.

Just last year, thousands across the country were sickened by a salmonella outbreak that was traced back to another Iowa egg farm. One woman profiled in the ABC News report, Sarah Lewis, became so sick from salmonella during the 2010 outbreak that she still takes heavy medications today.

Impact: After ABC News showed Sparboe Farms the hidden-camera footage, the company fired employees responsible for the alleged animal abuse and vowed to improve conditions.

Just before the initial ABC News report aired on "Good Morning America, McDonald's announced that it would no longer get its eggs from Sparboe. Target followed suit, cancelling its contract and pulling all Sparboe eggs off its shelves. In the following days, more grocery chains around the country pulled business from Sparboe.

In addition, the Food and Drug Administration sent a company-wide warning letter to Sparboe, citing inspections the agency had performed earlier in the year. In the warning letter, the FDA expressed concern that some of the conditions found there could put the farms at risk for a salmonella outbreak. It demanded immediate action from Sparboe.

Since the ABC News investigation, Sparboe has employed outside consultants to ensure the facilities address the FDA violations and prevent future issues. Sparboe also formed a task force to ensure all employees are properly trained on humane treatment of hens in its farms. The egg producer now says it is moving forward to make its company "better."